This work concerns the biogenesis of plasmalemma utilizing the basolateral membrane of the secretory cells of the salt gland as a model system. Salt stress causes a great amplification of this membrane and withdrawal of the stress results in rapid membrane resorption. Hypothetically, plasma membrane biogenesis occurs as an assembly line process involving functionally specialized compartments of the cell within which the Golgi is central to assembly. The process, the synthesis and assembly of phospholipid shall be studied by biochemical techniques that determine the lipid content and phospholipid synthetic enzyme activity of fractions and whole gland. Cytochemically, methods to localize many of the enzymes concerned with phospholipid synthesis will be developed as well as organo metallic analogues of lipids as tracers. The synthesis and assembly of enzymatic proteins shall also be studied, using NaK ATPase as a marker. These studies will use fractionation, gel profiles of fractions, pulse chase and immunochemistry with antibodies to the enzyme. The cytochemistry of NaK ATPase shall be further pursued as well as other membrane enzymes for both the apical and basolateral membrane. On destressing the ultrastructure biochemistry and cytochemistry of the resorption of the basolateral plasma membrane will be studies with emphasis on endocytosis, lysosomes and the Golgi. The experiments also lend opportunity to examine the possibility of recycling. Although these experiments will use whole gland, slices and fractions, we also use minilobules obtained of collagenase digestion and from this develop single cell system in culture. Finally control of membrane biogenesis will be examined, focusing on the probability that the initial signal is a cholinergic stimulus and the second involves a cyclic nucleotide. The latter experiments shall present an opportunity to induce secretory cells to produce new protein and phospholipid in vitro.